Maternity leave holiday calculator

Your leave doesn't stop when your maternity leave starts

Annual leave and maternity leave run side by side, not one after the other. Every week you're on maternity leave — Ordinary or Additional, paid or unpaid — your statutory holiday entitlement keeps building up exactly as if you were at your desk. Nothing about being on leave reduces it, and nothing about your leave year ending part-way through your maternity leave makes it disappear. What trips people up isn't whether leave accrues — it clearly does — it's what happens to it afterwards: when you're allowed to take it, what happens if a leave-year boundary falls in the middle of your maternity leave, and a carry-over rule that treats two halves of your "5.6 weeks" completely differently. That's what this page walks through, in order.

What happens month by month

Before you go: the leave you've already built up

Any statutory holiday you haven't used before your maternity leave starts is still yours. Some people take it in the run-up to their due date to push their actual last day at work later; others save it. Either is fine — there's no rule that says pre-maternity holiday has to be used by a certain date, beyond the normal rules for your leave year.

During the 52 weeks: what keeps accruing

Your statutory entitlement — 5.6 weeks a year under Working Time Regulations 1998, reg 13 and reg 13A — continues to build up for the entire time you're on maternity leave, not just the first 26 weeks. Gov.uk is explicit on this: "Employees continue to build up holiday entitlement and can take any holiday they've accrued before or after the leave." If your contract gives you more than the statutory minimum, check your handbook — the law only guarantees the 5.6 weeks continues to accrue in full; anything above that is whatever your contract says.

If your leave year ends while you're off

A 52-week maternity leave will almost always straddle at least one leave-year boundary. Because you were on statutory leave and physically couldn't take your holiday, the untaken balance doesn't lapse — it carries into the next leave year automatically, without needing your employer's sign-off. That's the subject of the worked example below, and the reg 13/13A split that governs exactly how it carries is covered further down.

Coming back: when you have to use it

Once you're back, ordinary use-it-or-lose-it rules resume for whatever you accrue in the current leave year. The leave that carried over specifically because maternity leave prevented you taking it isn't given a further statutory deadline the way sickness-related carry-over is (more on that below) — but it's still worth agreeing a plan with your employer soon after you're back, rather than letting it sit indefinitely.

A worked example

Aisha works full-time, five days a week. Her employer's leave year runs 1 January to 31 December, and her standard entitlement is 28 days — the statutory 5.6 weeks for a five-day week, made up of 20 days under reg 13 (the 4-week minimum) and 8 days under reg 13A (the extra 1.6 weeks).

• By 1 March 2027, when her maternity leave starts, Aisha has taken 6 days of her 2027 entitlement.
• Untaken balance at that point: 28 − 6 = 22 days.
• Her maternity leave runs the full statutory 52 weeks — 26 weeks' Ordinary plus 26 weeks' Additional Maternity Leave — from 1 March 2027 to 27 February 2028, so she's off for the rest of the 2027 leave year.
• Because she's on statutory leave for the remainder of 2027, none of that 22 days can be taken before the leave year ends on 31 December 2027. That's exactly the situation reg 13(14) and reg 13A(7A) cover — leave untaken "as a result of taking a period of statutory leave" — so all 22 days carry into 2028 automatically, and it applies equally to both her reg 13 and reg 13A leave.
• Because Aisha is employed throughout 2028 too, she accrues that year's full 28-day entitlement regardless of the two months of it spent on maternity leave — the gov.uk wording above doesn't say "a proportion," it says entitlement "continues to build up."
• Total holiday sitting on Aisha's balance on 28 February 2028, her first day back: 22 (carried over) + 28 (2028's entitlement) = 50 days.

That figure surprises a lot of employers, who sometimes assume maternity leave should shrink the year's entitlement proportionally. It doesn't — the only thing that gets pro-rated is a departing employee's final payment under reg 14, which is a different calculation entirely from someone who stays employed through the whole leave year.

Where this gets complicated

Carrying leave over isn't all-or-nothing

Almost every explanation of UK holiday entitlement treats "5.6 weeks" as one undifferentiated pot. It isn't. The 4-week reg 13 tranche and the 1.6-week reg 13A tranche are carried over under genuinely different rules, and the difference matters the moment maternity leave isn't the only thing going on.

The 4-week reg 13 tranche can only be carried over in three specific situations, all added or restated by the 2024 reforms: statutory leave (such as maternity) prevented you taking it (reg 13(14)); sickness prevented you taking it, in which case it must be used within 18 months of the end of that leave year (reg 13(15)); or your employer failed to give you a reasonable opportunity to take it, failed to encourage you to take it, or failed to warn you it would otherwise be lost (reg 13(16)–(17)) — in which case it keeps rolling forward until the first full leave year your employer stops failing to do those things (reg 13(18)).

The 1.6-week reg 13A tranche works differently. Historically it only carried over if a "relevant agreement" — in practice, your contract or staff handbook — said it could (reg 13A(7)), and there was no fallback if your employer's paperwork simply didn't cover it. Since 1 January 2024, reg 13A(7A) gives it the same automatic statutory-leave-prevented right as reg 13 — so for maternity leave specifically, both tranches now carry over the same way, as in Aisha's example above. But reg 13A has no equivalent of reg 13's employer-failure protection. If your employer never told you your leave would be lost, or never gave you a reasonable chance to take it, that rescues your 4-week reg 13 leave — it does not rescue your 1.6-week reg 13A leave, which falls back on whatever your contract says.

In practice this rarely bites when maternity leave itself is what stopped you taking your holiday — reg 13(14) and reg 13A(7A) cover you equally there. It matters most when the reason is something else: leave lost to a busy year, an employer who never mentioned use-it-or-lose-it, or a mix of both alongside a period of maternity leave. Knowing which tranche you're relying on, and why, tells you which protection actually applies.

Keeping-in-touch days

You can work up to 10 "keeping-in-touch" (KIT) days during maternity leave without it affecting your maternity leave or pay — gov.uk confirms both the 10-day limit and that your right to maternity leave and pay isn't affected by taking them. KIT days are optional and need agreement on both sides, including what you're paid for them. A KIT day is a day you work, not a day of holiday — using one doesn't use up any of the leave this page is about, and taking annual leave doesn't count towards the 10.

If your employer gets it wrong

The most common mistake is an employer treating leave that fell into a new leave year during maternity leave as simply lost, rather than automatically carried over under reg 13(14) and reg 13A(7A). Point them to the specific regulation — most payroll systems that get this wrong are working from a template that's never been updated for the 2024 changes, not from a deliberate decision.

If raising it informally doesn't resolve it, the next step is a formal grievance, then Acas early conciliation, which is a free, compulsory first step before any employment tribunal claim. Contacting Acas pauses your time limit while conciliation is ongoing. As of writing, that limit is normally 3 months less 1 day from the date of the underlying problem — but it's changing: for time limits that start on or after 1 October 2026, it extends to 6 months less 1 day. Check which applies to your dates before assuming you've run out of time.